Heater for boilers of the horizontal type



March 10,y 1931..

Jl W. CANNON HEATER FOR BOILERS OF THE HORIZONTAL TYPE Filed Nov.

2 Sheets-Sheet 1 3mm/bor, fo/7H V14 E@ /1/70/7 March l0, 1931.; J. w. CANNON .HEATER FOR BOILERS OF THE 4HORlZONTL TYPE Filed Nov. 14, 192s 2 sheets-sheet 2 31a/vanto@ 3,5m fa/7n VV [afina/7 @any #Amm C. 'mamen/1 Patented Mar. 10, 1931 errar JOHN W. CANNON, or :PLerNriELn New ana-snr HEATER FOR BOILERS F THE HORIZONTAL TYPE Application filed November 14, 1923. Serial No. 319,38?.

rlhis invention relates to heaters, and more particularly to water heaters of the househeating boiler type.

It is the general purpose and object of the invention to provide a heater of the character referred to which will secure a very high eficiency from the combustible fuel, thereby resulting in economy of operation. A further object of the invention is to provide a construction of heater which, while realizing such eficieney and economy in operation,

is extremely simple in construction and economical of production.

Further objects of the invention will appear hereinafter and will be realized in and through the construction and arrangement of pai-ts shown in the drawings, wherein Fig. represents a central vertical sectional view through a lieater'constructed in accordance with my invention; Fig. 2 a horizontalV sectional view corresponding to the line 2 2 of F ig. 1 and looking in the direction of the arrows; Fig. 3 a vertical sectional view corresponding to the line 8 8 of Fig. 1 and looking in the direction of the arrows; F ig. i a View, similar to Fig. 1, showing a modified form of heater embodying my invention; Fig. 5a horizontal sectional view corresponding to the line 5 5 of Fig. a and looking in the direction ofthe arrows; and

Fig. 6 a verticalsectional view corresponding tothe line 6-G ofv Fig. 4 and looking in the direction of the arrows.

Referring first to Figs. 1 to 3 inclusive, 1 denotes the bottom wall, 2 theV side walls, 3 the top and t and 5 the front and rear walls, respectively, of a boiler of the section-type. The boiler shown in both forms of my invention is preferably rectangular in horizontal and vertical section; It is provided with a firebox A, the said firebox comprising a bottom wall. 6, which extends from the'front to the rear of the boiler and is spaced from the bottoni wall of said boiler; with side walls 7, which extend above the Awater space in the boiler; and with front and rear walls constituted by the front and rear walls 4: and 5 of the boiler. The top' of the yfirebox comprises upper horizontal wall 8 which exo tends the full length of the heater, merging rearwardly extending side lues 10, the rear ends of which communicate with the forwardly extending flue 11 which discharges linto a stack 12.

Mounted in the lower portion of the firebox is a combustion chamber comprising a bottom wall 13 and a top wall lll.' The bottom wall is supported on lugs 15a projecting inwardly from the sides 15, intermediate the top and the bottom of said sides. The top wall lll is provided with grooves 14a by which it is seated on top of the side walls. A coinbustion passage l-is formed within and between the parts 18, le and 15. The rear of the bottom wall extends upwardly, as shown at 13a, as far as the top 14, and forms with the rear end lof said top an outlet 17 for products of combustion.

The parts 13a, 14 and 15 are composed `of refractory material having a thermal conductivity in excess of 0.006 calorie/cm/see/OC., examples of such materials being silicon carbide (conductivity .0311 units) and fused alumina (conductivity .010 units).v Silicon carbide is particularly suitable as in addition to its high thermal conductivity it possesses an veinissivity which has been found to be approximately 97% of that of black bodies, rendering it particularly well fitted to transmit heat by radiation to the metal walls of the water jacket of ythe furnace. Its properties also cause the walls of my combustion chamber when built of this material to maintain a be noted that the lugs or ledges 15a support the bottom 13 above the bottom 6 of the fire'- boX, there beingy a horizontal flue 19 pro- `vided between the parts 6 and 18, the inlet to which flue is formed by an opening 20a in a door 20 which closes the rear of the "space comparatively uniforin temperature with a between the walls 6 and 8 of the iireboX.

The air inlet opening m is controlled by a damper 21 which is operated by an arm 22V and a chain 23 from a thermostat (not shown) which thermostat is adapted to operate a motor in a casing 24 through the conducting wires B and C in a manner well known to those skilled in the art. The thermostat will be installed in the particular place the temperature whereof is to operate the damper. Instances of thermostatically controlled mechanisms such as indicated herein are the Honeywell controly and the control known to the trade as the Regitherm.

25 denotes a gas supply pipe which projects through the door 26 which closes the front of the space between the walls 6 and 8, the said pipe discharging into a header 27 provided with a horizontal series of burner nozzles 28. The supply of gas to the header 27 is shown as controlled by a slow moving valve 29 (such as is described in copending application Serial No. 321,254, filed Nov. 22, 1928) which may also be operated by means of a motor, indicated generally at 30, and conductors D and E leading to a thermostat (not shown)` which is located in the particular place the temperature of which is to control the supply of 'gas to the burner. Control member 30 may be identical with member 24 but is shown separately for convenience in drawing.

With the parts constructed and arranged as described, the burners 28 will be lighted by means of a pilot burner such as is indicated by 61 in lig.V 1 or 61 in Fig. 4, and air to support the combustion Vof the gas will. be supplied through the inlet 20a, Hue 19, and port 18, where it will mingle withv the gas and be burned in the flue or pass 16. The arrangement of the port 18 and of the burner nozzles 28 is such that the air will be entrained by the gas issuing from said nozzles and mingled with such gas in such proportion as to enable the gas to be consumed Vwithin the combustion space or passage 16.

The walls 13, 14 and 15, being made of the material specified, will radiate heat resulting from combustion to the flue 19, thereby securing great efficiency in the combustion of the mixture of gas and air within the flue or pass 16. By locating the burner header 27 in. the front of the combustion chamber and above the port 18, the gas is preheated in such header prior'to its combustion, bot-h by the heated air delivered through said port and by the heat in the combustion chamber.

The burning gases and products of combustion pass through the port 7 into the rear of the upper portion of the rebox, whence they iow forwardly through the flue 31 formed between the parts 7, 8 and 14, and the products are then delivered through the vertical flues 9 into the rearwardly extending flues 10 and thence into the forwardly extending central flue 11.

By reason of the construction and arrangement of parts, the air in the flue 19 and the products of combustion and gases in the flue 81 will be heated by radiation from the combustion chamber, as will also the water in the adjacent portions of the boiler. rlhe arrangement of the flues 10 and 11 insures the heating 0f the vapors evolved from the water in the boiler.

in Figs. 4 to 6 there is shown a modification of my invention wherein the boiler proper is substantially identical with that shown in Figs. 1 to 3; and corresponding parts of the boilers in both forms are designated by the same reference characters. In the second form, however, the combustion chamber is of the two-pass type and comprises a bottom wall 32, a top or cover wall 33, and side walls 34 provided with ledges 34a which support a partition 35 extending rearwardly from the door 26 toward but spaced from the rear wall 36, thereby to provide a passage 37 around the rear `of the said partition. The top of the combustion chamber is provided adjacent to the front of the boiler and the door 26 with a flue or outlet 38 by which the products of combustion are discharged into a horizontal flue 39, whence they pass through vertical fines 40, adjacent the rear of the boiler, into forwardly extending side flues 41 which communicate at their front ends with a front transverse flue 42 which in turn communicates with a central rearwardly extending horizontal flue 43, the last mentioned iiue discharging into the stack 44.

rihe front of the flue 38 is formed by a transverse slab 38a which rests on top of the partition 35. The walls 32-38a inclusive are made Vof material having very high heat transmitting qualities at high temperatures, silicon Vcarbide for example, having a thermal conductivity greater than 0.006 calorie/ cm/O C./sec., as is the `case with the material employed for the combustion chamber in the form of my invention shown in Figs. 1 to 3 inclusive.

rIhe door 26 is provided with a transverse opening 26a above the wall 32 and below the partition 35 and extending preferably nearly the full width of the lower pass of the combustion chamber. Projecting outwardly from this opening isa casing45 which casing, in vertical section, is in the form of a Venturi tube. A gas supply pipe 46, which is provided with a slow opening valve 47 such as is described in the copcnding application referred to, delivers gas to a header 48 arranged in front of the outer end of the casing 45. From this header, burner tubes 49 project axially into the casing 45, each tube being provided with a flattened delivery end 49 each having an elongated delivery slot 50. The slots 50 are'arranged adj allO cent to the contracted portion of the Venturi tube casing 45, this arrangement insuring an efficient entraining by the gas of the air supplied to the outer end of the casing, whereby suiiicient air will be admixed with `the gas to enable the mixture to be consumed in the combustion space formed by the liues below, above and around the partition 35.

The valve 47 may be operated by a thermostat (not shown) installed in the particular place the temperature whereof is to control the supply of gas to the header. 51 indicates conventionally a thermostatically operated control for the valve, the said control being provided with wires 52 and 53 leading to the thermostat.

The supply of air to the Venturi tube casing is controlled by a pair of dampers 54 operated by arms 55 connected to a link 56, the link and arms in turn being connected by a chain 57 to a thermostatically operated control indicated generally at 58, the wires 59 and 60 leading from said control to the thermostat (not shown). As pointed out in connection with the form of my invention shown in Figs. l to 3, any standard or suitable type of thermostatically operated control mechanism may be employed.

With the parts constructed and arranged as shown in Figs. 4 to 6, the operation will be as follows: Gras will be supplied to the pipe 46 in the usual manner and from there through the slow opening valve 47 to the header 48 where it is preheated after which the gas passes into the combustion chamber 'where it is ignited as' it emerges from the slots 50. rIhe streams of gas, being delivered at the contracted portion ofthe Venturi'tube casing, will entrain in a most eliicient manner the air supplied to the front of said chamber, and the ignited mixture will be burned in the combustion chamber. The parts will be so proportioned and constructed that complete combustion is preferably obtained within the chamber, the best results being accomplished when the end of the flame reaches the port 38. The water within the boiler will be heated in a very eflicient manner by radiation from the combustion chamber and from the walls of the iirebox; while the arrangement of the iues 4l and 43'insures efficient heating of the vapors evolved from the water in the boiler.

A principal advantage of my fuel burning arrangement is that it secures substantially complete combustion of the fuel at all times. Perfect combustion is particularly hard to obtain when a large flow of gas is turned on while the combustion chamber is cold. This is because in such cases the rate of combustion in the cold combustion chamber is so low that the oxidation ofthe gas is not complete, and a heavy deposit of soot isformed within the combustion chamber. I avoid this trouble however, by admitting only a limited amount of gas until such time as the interior of the combustion chamber has been heated to incandescence afterwhich a greatly increased rate of gas flow is permissible.

This adjustment of the rate of gas flow to produce complete combustion at all times is obtained by the use of a slow opening valve which permits the initial gas flow to the combustion chamber t0 be maintained at a rate which is a small fraction of the rate after the valve has been fully opened. In this way complete combustion of the gas is secured at allV times. After the walls of my combustion chamber have been heated to incandescence, it is possible to secure complete combustion of gas in the chamber at a very high rate due tov should not be considered as limited to the speciiic purpose illustrated.

Having thus described my invention, what I claim is:

l. An apparatus of the character described comprising a boiler casing having a substantially horizontally extending rebox therein, a horizontally extending combustion chamber in said lirebox, the firebox being so situated as to transmit heat by radiation to the vinner wall of the casing and thence by conduction to the water below and around it, the said combustion chamber comprising upper and lower walls and side walls providing a combustion space therebetween, there being a flue for supplying air to one end of the combustion chamber, the said flue being located between the bottom of the combustion chamber and the bottom of the iirebox and communicating with one end of the comb-ustion chamber by a port, the walls of the combustion chamber being comprised of silicon carbide whereby the heat is easily conducted to the incoming air in said flue and radiated through the incoming air to the adjacent Water walls, a burner above such port arranged to discharge into the combustion chamber, there being a flue above the combustion chamber and communicating therewith by a port at the end of the chamber opposite the burner, and flues extending longitudinally of the heater above the liquid-containing space therein and adapted to receive products of combustion from the second flue.

2. An apparatus of the character described comprisinga boiler casing, a lirebox within the casing and extending longitudinally and horizontally thereof, the lower portion of thc y irebox extending into the liquid'in said casing and the upper portion of the irebox communicatingfat one end with horizontally extending flues located in the vapor-containing space of the boiler, a combustion chamber in the lower portion of the iirebox and extending vsubstantially parallel with the bottom thereof and providing between the bottom of the combustion chamber and the bottom of the irebox a horizontal flue for supplying air to the combustion chamber through a port at one end of the bottom of said chamber, the walls of the combustion chamber being composed of silcon carbide whereby heat is conducted in large quantities to the incoming air in said flue and is also radiated in large quantities to the water in the lower part of the casing, and a burner located above the said port and arranged to discharge into the combustion chamber, there being a flue between the top of the combustion chamber the top of the iirebox and communicating with the combustion chamber through an outlet located at the opposite end of the chamber from said burner, the end of the last mentioned flue which is opposite the said outlet communicating with the fines in the vapor space.

3. An apparatus of the character c escribed comprising a horizontally extending boiler casing, a horizontally extending lirebox said casing and having its lower portion submerged in the liquid therein and paced from the adjacent walls of the boiler casing, a combustion chamber of high heat-radiating material located in the lower portion of the said irebox and extending substantiallv from o one end to the other thereof, and means for delivering' gaseous fuel to one end of said combustion chamber, there being a flue for air envr tending beneath the bottom of said combustion chamber in the said firebox for supplying air to the gaseous fuel burned therein, whereby the air to support combustion will be heated through the bottom wall of the combustion chamber, and the water in the lower part of the casing will be heated by radiation emitted from the bottom wall of the combustion chamber.

d. An apparatus of the character descri ed comprising a horizontally extending boiler casing, a horizontally extending rebox in said casing and having its lower portion submerged in the liquid therein and spaced from the adjacent walls of the boiler casing, a combustion chamber of high heat-radiating material located in the lower portion of the iirebox and extending substantially from one end to the other thereof, means for delivering gaseous fuel to one end of said con bustion chamber, there being a tiue for air extendingbeneath the bottom of said combustion chamber in the said iirebox for sup.- plying air to the gaseous fuel burned thereir, whereby the air to support combustion will be heated through the bottom wall of the combustion chamber, temperature controlled means for regulating the supply of air to the said flue, and temperature controlled means for. regulating the supply ofv gaseous fuel to combustion chamber.

5. An apparatus of the character described comprising a boiler casing having a substantially horizontally extending firebox therein, a horizontally extending combustion chamber in said rebox, the walls of the combustion chamber being composed principally of material having high heat-radiating qualities at high temperatures, and having a thermal conrductivity greater than 0.006 calorie /cm.3 o (3./ sec., doors closing the opposite ends of said firebox, one of the doors having an opening therethrough communicating with one end of the combustion chamber, the second door containing an adjustable inlet for air to be preheated y passage under thev lower wall he combustion chamber in a direction opposite to the flow of the adjacent combustion ga es, an air duct leading from the adjustable opening in the other door and lying between the floor of the radiating combustion chamber and the bottom wall of the IireboX, and means for delivering fluid fuel through Said opening into said combustion chamber.

6. in apparatus of the character described comprising a boiler casing, a fireboX within the casing and extending longitudinally and horizontally thereof, a combustion chamber i'i the lower portion of the firebox and proii g', between the bottom of the combustion chamberV and the bottom of the firebox, a horizontal flue for supplying air to the combustion chamber through a port at one4 end of the bottom of said chamber, the fire box being so situated as to transmit heat by radiation to the inner wall of the casingV and thence by conduction to the water below and around said casing, a burner header in the said combustion chamber located above the said port and arranged to discharge gaseous fuel into the combustion chamber, the said combustion chamber being composed principally of material having high heat-radiating Jualities at high temperatures, and having a thermal conductivity greater than 0.006 calorie/cm-3/o /sec., whereby air supplied through the said flue will be heated and the gas in the burner header will be heated by such air and by the heat within the combustion chamber, while the water in the lower part of the casino is heated by radiation from the bottom wall of the combustion chamber.

l". Ein apparatus of the character described comp 'ising a boiler casing having a substantially horizontally extending irebonr therein, a 'horizontally extending combustion chamber in said lirebox, thewalls of the combustion chamber being composed principally of ma- "al having high heat-radiating qualities at temporaturesvx and having a thermal conmictivity greaterthan 0.006 ealorie/cm-3/O C./ sec., doors closing the opposite ends of said firebox, one of the doors having an opening bustion chamber, and the water in the lower part of the casing will be heated by radiation emitted from the bottom wall of the combustion chamber.

8. An apparatus of the character described comprising a horizontallyextending boiler, a horizontally extending lireboX mounted in said boiler and extending substantially the full length thereof and having its walls spaced from the boiler casing and its lower end submerged in the liquid in said casing, a combustion chamber having thin walls lot' high thermal conductivity and high heat radiating qualities mounted in the tireboX and extending substantially from the front Vto the rear thereof, the walls of said combustion chamber being arranged in proximity to the side walls of the ireboX, a burner arranged to discharge into one end of said combustion chamber, means for conveying iuid fuel tosaid burner, a slow opening valve having thermostatic control for regulating the rate of flow of fuel to the burner to prevent accumulation of soot therein, and a flue extending beneath the bottom of said combustion chamber for supplying preheated air to the fluid fuel burned therein.

In testimony whereoic I aHiX my signature.

' JOHN W. CANNON. 

